Related papers: Minimum Shear Viscosity over Entropy Density at Ph…
We present a calculation of eta/s for the meson gas (zero baryon number), with the viscosity computed within unitarized NLO chiral perturbation theory, and confirm the observation that eta/s decreases towards the possible phase transition…
We investigate the shear viscosity $\eta$ and the entropy density $s$ of strongly coupled $\mathcal{N}=4$ super Yang-Mills (SYM) plasma in late time of hydrodynamic evolution with AdS/CFT duality and Bjorken scaling. We use correlation…
In order to understand the detailed dynamics of systems produced in $pp$ collisions, it is essential to know about the Equation of State (EoS) and various thermodynamic properties. In this work, we study the shear viscosity to entropy…
We review the modern view of fluid dynamics as an effective low energy, long wavelength theory of many body systems at finite temperature. We introduce the concept of a nearly perfect fluid, defined by a ratio $\eta/s$ of shear viscosity to…
The remarkably small shear viscosity to entropy density ratio $\eta/s < 0.5$ of the quark-gluon plasma (QGP) is a key insight from heavy ion experiments. Nonetheless, the basic understanding of this `observable' still seems to be…
In this contribution we summarize recent progress in understanding the shear viscosity of strongly correlated dilute Fermi gases. We discuss predictions from kinetic theory, and show how these predictions can be tested using recent…
The specific shear viscosity $\bar\eta$ of a classically rotating system of nucleons that interact via a monopole pairing interaction is calculated including the effects of thermal fluctuations and coupling to pair vibrations within the…
Attractive emulsions near the colloidal glass transition are investigated by rheometry and optical microscopy under shear. We find that (a) the apparent viscosity \eta drops with increasing shear rate, then remains approximately constant in…
We describe recent attempts to extract the shear viscosity of the dilute Fermi gas at unitarity from experiments involving scaling flows. A scaling flow is a solution of the hydrodynamic equations that preserves the shape of the density…
We calculate the partial electron shear viscosity $\eta_{ee}$ limited by electron-electron collisions in a strongly degenerate electron gas taking into account the Landau damping of transverse plasmons. The Landau damping strongly…
The shear viscosity $\eta$ for a dilute classical gas of hard-sphere particles is calculated by solving the Boltzmann kinetic equation in terms of the weakly absorbed plane waves. For the rare-collision regime, the viscosity $\eta$ as a…
In this perspective review, we present a concise yet multifaceted overview of the pivotal role played by the the shear viscosity to entropy density ratio across various physical contexts. After summarizing some of the main aspects of the…
Supercooled liquids exhibit complicated dynamical behaviors: At the microscopic level, the dynamics is heterogeneous spatially, known as dynamic heterogeneity. At the macroscopic level, the shear viscosity $\eta$ decreases as shear rate…
A theoretical framework for the calculation of shear and bulk viscosities of hadronic matter at finite temperature is presented. The framework is based on the quasi-particle picture. It allows for an arbitrary number of hadron species with…
We show from covariant transport theory that, for a massless ideal gas equation of state, even a small shear viscosity to entropy density ratio $\eta \approx s/(4 \pi)$ generates significant 15-30% dissipative corrections to elliptic flow…
Equilibration of highly excited baryon-rich matter is studied within the microscopic model calculations in A+A collisions at energies of BES, FAIR and NICA. It is shown that the system evolution from the very beginning of the collision can…
We investigate the temperature dependence of the shear viscosity ($\eta$) and bulk viscosity ($\zeta$) of the gluon plasma using lattice QCD over the range 0.76--2.25$\,T_c$, extending from below the transition temperature $T_c$ across the…
We demonstrate that measurements of rapidity differential anisotropic flow in heavy ion collisions can constrain the temperature dependence of the shear viscosity to entropy density ratio {\eta}/s of QCD matter. Comparing results from…
For an isolated assembly that comprises a system and its surrounding reservoirs, the total entropy ($S_{a}$) always monotonically increases as time elapses. This phenomenon is known as the second law of thermodynamics ($S_{a}\geq0$). Here…
In the hadronic phase, the dominant configuration of QCD with two flavors of massless quarks is a gas of massless pions. We calculate the bulk viscosity (zeta) using the Boltzmann equation with the kinetic theory generalized to incorporate…